Field of the Invention
The present invention relates to an imaging lens, an optical apparatus equipped with the imaging lens, and a method for manufacturing the imaging lens.
Related Background Art
A compact imaging lens suitable for a photographic camera, a video camera, and the like having an angle of view of about 50 degrees and relatively small value of an f-number has been proposed. Moreover, in such an imaging lens, there has been known a lens configuration including, in order from an object side, a first lens group composed of a negative lens and a positive lens, an aperture stop, and a second lens group composed of a cemented lens constructed by a negative lens cemented with a positive lens, and a positive lens, for example, Japanese Patent Application Laid-Open No. 9-189856.
However, in such a conventional imaging lens, when the whole lens is moved for focusing, the total lens length becomes long upon focusing from an infinity object to a close object. Moreover, various aberrations cannot be sufficiently corrected upon focusing on a close object.
Moreover, in a conventional camera equipped with such an imaging lens, when the camera becomes small, thin and lightweight, holding of the camera becomes difficult resulting in increase in shooting error cause by a camera shake or the like. In other words, the image is deteriorated by an image blur during exposure caused by a minute camera shake triggered by a hand movement occurred upon shooting (for example, a camera shake generated upon depressing a release button).
Accordingly, there has been known a method for correcting an image blur with installing a driving system that shifts a portion of lens as a shift lens group in a direction perpendicular to an optical axis, a detection system that detects a camera shake, and a calculation system that controls the driving system on the basis of a detection result of the detection system into such a conventional imaging lens.
However, in the above-described imaging lens capable of correcting an image blur, there has been a problem that various aberrations cannot be excellently corrected, and optical performance varies upon shifting the shifting lens group.